March 2012 issue | Plant Omics Journal

Changes in antioxidant enzymes activity and plant performance by salinity stress and zinc application in soybean (Glycine max L.)

Weria Weisany, Yousef Sohrabi, Gholamreza Heidari, Adel Siosemardeh, Kazem Ghassemi-Golezani

Abstract
An experiment was conducted to investigate the effects of zinc application and salinity stress (0, 33, 66 and 99 mM NaCl) on some morphological and physiological parameters of soybean (Glycine max L., var. Williams). Results showed that zinc application improved shoot length, root fresh and dry weight and shoot fresh and dry weight under all salinity treatments. The catalase (CAT), ascorbate peroxidase (APX), polyphenoloxidase (PPO) and peroxidase activity (POD) and also proline content increased as a result of salinity stress. Lipid peroxidation and hydrogen peroxide concentration under the highest salinity were significantly greater than those under other treatments. However, lipid peroxidation and hydrogen peroxide concentration under salinity treatments significantly reduced as a result of zinc application. Zinc may act as a scavenger of ROS for mitigating the injury on biomembranes under salt stress. Adequate zinc also prevents uptake and accumulation of Na in shoot, by increasing membrane integrity of root cells.

Pages 60-67 | Full Text PDF

Suppression of chickpea (Cicer arietinum L.) Fusariums wilt by Bacillus subtillis and Trichoderma harzianum

Haidar Moradi, Bahman Bahramnejad, Jahanshir Amini, Adel Siosemardeh, Kaveh Haji-Allahverdipoor

Abstract
We studied the effect of Bacillus subtillis and Trichoderma harzianum Rifai, in commercial formulations, alone or in mixture, on soluble protein content, ß-1, 3-glucnase enzyme activity and suppression of Fusarium wilt disease caused by Fusarium oxysporum f.sp ciceris in Hashem and Pirooz chickpea cultivars. Experiment was conducted in a factorial experiment based on randomized complete design with three replications under controlled greenhouse condition with aggressive isolate of F. oxysporum f.sp ciceris and B. subtillis, T. harzianum treatments in liquid and seed coating inoculation methods. Disease severity was significantly reduced by B. subtillis, T. harzianum and their mixtures (about 40%). Although the combination of these bio-control agents was effective in controlling Fusarium wilt disease but did not differ significantly from bio-control treatments individually. Hashem cultivar exhibited significantly higher level of resistance compared to Pirooz cultivar after inoculation with bio-control agents. Significantly higher levels of soluble protein content and ß-1, 3-glucnase activity was observed in chickpea cultivars after inoculation with B. subtillis, T. harzianum compared to control. Hashem cultivar exhibited significantly higher levels of soluble protein content and ß-1, 3-glucnase activity in compared to Pirooz cultivar, which apparently associated with establishment higher level of resistance to Fusarium wilt. Results of this study indicated that B. subtillis and T. harzianum effectively suppress the Fusarium wilt and increasing the protein content and ß-1, 3-glucnase enzyme activity might have contributed to inducing systemic resistance after treatment with bio-control agents. Application of B. subtilis and T. harzianum either singly or in combination in both seed and liquid inoculation methods protect chickpea from F. oxysporum f.sp ciceris infection indicating that the importance of application of biocontrol agents.

Pages 68-74 | Full Text PDF

Data mining of Arabidopsis thaliana salt-response proteins based on bioinformatics analysis

Guo Meili, Gao Weixi, Yu Xuejuan, Zhou Chunxi, Liu Fujun, Liu Xin

Abstract
Salt stress limits the growth and productivity of many plants. To further understand plant protein salt-response mechanisms, the proteins of model plant Arabidopisis thaliana was selected and mined based on bioinformatic analysis and experimental biology verification. With the features of salt-response, 292 of 10,835 reviewed Arabidopsis thaliana proteins were screened from Uniprot public proteins database. Among 292 salt-response proteins, 67, 71, and 54 proteins showed the cross-talk with cold, drought and heavy metal stress, respectively. Function classifications revealed the above four groups (292, 67, 71, and 54 proteins) were mainly associated with reactive oxygen species scavenging and defense, catalytic activity, signal transduction, and energy metabolism. Activities of superoxide dismutase and peroxidase in both Arabidopisis thaliana root and leaf were determined under salt (150mmol.L-1 NaCl), cold (10), drought (200mmol.L-1 mannitol), and heavy metal (10µmol.L-1 CdCl2) stress. The experimental results were consistent with bioinformatic analysis. This work improves our knowledge of salt tolerance and provides clues to discover salt tolerance protein targets for plant growth and crop productivity.

Pages 75-78 | Full Text PDF | Supplementary data

Morpho-physiological improving effects of exogenous glycine betaine on tomato (Lycopersicum esculentum Mill.) cv. PS under drought stress conditions

Mohammad Ali Rezaei, Ibrahim Jokar, Mahlagha Ghorbanli, Behzad Kaviani, Ardashir Kharabian-Masouleh

Abstract
Drought stress reduces the yield and production of tomato (Lycopersicum esculentum Mill.). Tomato does not naturally accumulate glycinebetaine (GB) in the cells under natural conditions. Effects of exogenous glycinebetaine on some morpho-physiological characteristics of Lycopersicum esculentum Mill. cv. PS was evaluated at different levels of drought stress. The experiment was conducted in a factorial design based on completely randomized block design (RCBD) with four replications. Seeds were germinated and arranged in pot conditions. Plants were watered weekly, bi-weekly and tri-weekly once as drought stress and irrigation was based on 100% of field capacity (FC). Exogenous glycinebetaine was applied as foliar at three levels (0, 5 and 10 mM) in three stages with 10 days interval. Root length, leaves number, total leaf fresh weight, total leaf dry weight, leaf area index, relative water content (RWC), and stress tolerance index (STI) were analyzed in the vegetative stage. Moreover, flowering number, fruit number and fruit weight were recorded during reproductive period. Results showed that the vegetative growth parameters [shoot height (maximum; 59.75 cm, minimum; 40.25 cm), root length (highest; 58.25 cm, lowest; 38.25 cm), leaf number (largest; 47.50, lowest; 16.50), leaf area (most; 819.21 mm2, least; 305.63 mm2)] and physiological characteristics [total shoot fresh weight (maximum; 52.68 g, minimum; 48.23 g), total shoot dry weight (maximum; 51.18 g, minimum; 36.67 g), relative water content (highest; 47.08, lowest; 25.95) and stress tolerance index (highest; 1.220, lowest; 0.548)] decreased with the increment of drought stress. In addition, all the above mentioned traits increased (70%, 73%, 187%, 193%, 168%, 9%, 72% and 122%, respectively) by exogenous application of glycinebetaine, significantly. Reproductive growth parameters [the number of flower (largest; 46, least; 23), fruit number (largest; 45, least; 22) and weight of fruit (maximum; 34, minimum; 20)] decreased under drought stress and increased significantly by 86%, 115% and 125%, respectively under exogenous application of glycinebetaine. Based on studied reproductive growth parameters in two levels of drought stress, the 10 mM exogenous glycinebetaine was the best treatment and recommended to alleviate effects of drought condition.

Pages 79-86 | Full Text PDF

The effect of exogenous glycine betaine on yield of soybean [Glycine max (L.) Merr.] in two contrasting cultivars Pershing and DPX under soil salinity stress

Mohammad Ali Rezaei, Behzad Kaviani, Ardashir Kharabian Masouleh

Abstract
Salinity stress restricts growth of soybean plant [Glycine max (L.) Merr.]. Glycine betaine (GB) is among osmoprotectant compounds that are produced in tolerant plant species in response to environmental stresses. Soybean is sensitive to soil salinity and is classified as a low-ccumulator of glycine betaine. Therefore, this study was performed to evaluate the salinity tolerance of two contrasting soybean [Glycine max (L.) Merr.] cvs. Pershing and DPX at field saline soils (EC=11.1 dS/m-1). The exogenous glycine betaine (Exo-GB) treatments (0, 2.5, 5, 7.5 and 10 kg/ha) were applied in six foliar and near the flowering stages. During the growth period the amount of endogenous-glycine betaine (Endo-GB) was measured in ten foliar stages and in leaves of seeding stage. Results showed that the uptake of Na+ decreased in response to increment of Exo-GB levels, in which tolerant cv. DPX (24%) had a greater capacity to prevent Na+ uptake. Endo-GB had higher concentrations in younger leaves than in mature leaves. Exo-GB increased the number of lateral branches significantly (33%) and especially pods per plants (49%) in cv. DPX. There was no difference in seed number per pod between controls and all levels of Exo-GB treatments in two cultivars. All treatments of Exo-GB significantly increased weight of thousands grain (highest; 71% in 10 kg ha-1 GB) in salt tolerant cv. DPX. Application of Exo-GB on weight of thousands grain was cultivar-, dose-, and time-dependent. The grain yield of soybean was increased by foliar applications of Exo-GB. This was due to significant increase in number of lateral branches and pods and weight of thousands grain, without significant different between cultivars.

Pages 87-93 | Full Text PDF

Genome-wide analysis of cytosolic and chloroplastic isoforms of glutathione reductase in plant cells

Ahmad Tahmasebi, Farzaneh Aram, Mansour Ebrahimi, Manijeh Mohammadi-Dehcheshmeh, Esmaeil Ebrahimie

Abstract
In recent years regarding the climate change and subsequent environmental stresses, there has been an increasing interest in finding and characterizing of new antioxidant enzymes. Glutathione reductase (GR) is an antioxidant enzyme with central role in maintaining the reduced glutathione pool during stress. So far, however, there has been little discussion on genome-wide analysis of this enzyme. In this study, different computational biology approaches (EST analysis, feature selection, and evolutionary analysis) were exploited to identify the key protein properties influencing on cytosolic and chloroplastic isoforms of glutathione reductase in plants. A specific targeting signal peptide was found in chloroplastic isoforms, while cytosolic isoforms carry a cytosolic domain. This domain may affect the biochemical properties of the different GR isoforms. Moreover, specific functional motifs were discovered in cytosolic and chloroplastic isoforms implying a link between subcellular localization of GR and functional. Phylogenetic analysis of GR nucleotide and protein sequences showed that diversification of this gene family could be dated back to the early stage of plant evolution, possibly by duplication event before the divergence of monocot and dicot. A high degree of gene structure conservation of localized isoforms in the same subcellular compartment also reflects this process providing an evidence for a close relationship among proteins located in the same subcellular compartment. Study of glutathione reductase expression by EST analysis highlighted cytosolic isoforms as the main isoforrm responding to stress condition.

Pages 94-102 | Full Text PDF | Supplementary data

Molecular cloning and characterization of two Trithorax-Group genes from Phaseolus vulgaris roots and symbiotic nodules.

Juan Manuel Quiceno-Rico, José Alberto Camas-Reyes and Raúl Alvarez-Venegas

Abstract
In eukaryotes, trithorax group proteins play critical roles in the regulation of transcription, cell proliferation, differentiation and development. In this work we report the molecular cloning and characterization of two cDNAs, PvuTRX1h and PvuASH1h, from the common bean Phaseolus vulgaris, both of which encode polypeptides homologues of trithorax group members described in animals and yeast. A full length clone of PvuTRX1h was isolated from total RNA prepared from roots and consisting of a 3270 bp ORF encoding 1089 amino acids, while the PvuAsh1h consists of a 1446 bp ORF encoding 481 amino acids. Characterization of the isolated sequences revealed that they contain all the canonical domains present in proteins from the TRX (trithorax) and ASH1 families. A comparison of the PvuTRX1h and PvuASH1h SET-domain sequences with homologous proteins from plants, animals and yeast, revealed that PvuTRX1h is phylogenetically related to the TRX family of histone lysine methyltransferases while PvuASH1h clusters with members of the ASH1 family. Quantitative RT-PCR (reverse transcription polymerase chain reaction) analyses of transcript abundance in roots and nodules, at different developmental stages, demonstrated that PvuTRX1h is particularly abundant at early stages of nodule development, whereas PvuASH1h functions at the stages of highest nitrogen-fixing activity of the nodules, suggesting that these genes could be involved in the formation of nitrogen-fixing nodules in P. vulgaris. This work reports the presence and characterization of Trithorax-group homolog genes in P. vulgaris and their expression patterns during nodule development.

Pages 103-114 | Full Text PDF | Supplementary data

The nitric oxide production and NADPH-diaphorase activity in root tips of Vicia faba L. under copper toxicity

Ting Zou, Li Ping Zheng, Hui Yan Yuan, Ya Fei Yuan, Jian Wen Wang

Abstract
Copper (Cu) toxicity on plants has become a major problem with increasing agricultural and environmental pollution. The effect of Cu on NADPH-diaphorase (NADPH-d) activity, commonly employed as a marker for nitric oxide synthase (NOS) activity and nitric oxide (NO) production, were investigated in root tips of Vicia faba L. We found that Cu stress stunted root growth and development of root hair. Cu treatment also caused an increase in NADPH-d activity and NO release in roots. Application of the NO donor sodium nitroprusside (SNP) efficiently alleviated the copper toxicity effects. The Cu-induced NO in vascular bundles was associated primarily with the presence of the induced NADPH-d activity. Our results suggested that NOS-like enzyme, but not the nitrate reductase, was the source of inducible NO generation in roots of V. faba under Cu stress. This is the first report on NADPH-d activity and its distribution in plants under Cu toxicity.

Pages 115-121 | Full Text PDF

Sequence variability and expression pattern of the dehydrin gene family in Populus alba × P. tremula var. glandulosa

Eui Cheol Kim, Hyo Shin Lee, Dong-Woog Choi

Abstract
The dehydrin (Dhn) genes occur as multi-gene families in the plant genome and are suggested to play a protective role in cold and drought tolerance. Here, we have identified 10 unique dehydrin genes (PoDhn) from poplar (Populus alba × P. tremula var. glandulosa), 6 of which have the full ORF. The PoDhn1 encodes for SK2-type, PoDhn2 and PoDhn7 for Kn-type, PoDhn3 for K3S-type, and PoDhn5 and PoDhn6 for the Y3SKn-type dehydrins, respectively. Results of gene expression analysis demonstrated that most of the PoDhn genes were expressed under normal growth conditions and the transcription level of the PoDhns increased by abiotic stress treatment. In particular, PoDhn2 and PoDhn7 transcripts increased dramatically by both cold and drought treatment and PoDhn5 was up-regulated by only drought stress. These results may be useful in further studies of PoDhn genes, including investigations into the mechanisms underlying gene expression, the nature of their variation, and their physiological functions.

Pages 122-127 | Full Text PDF | Supplementary data

Genetic relationships among Achillea tenuifolia accessions using molecular and morphological markers

M. Rahimmalek

Abstract
ISSR and morphological markers were used to detect genetic diversity in several genotypes of Achillea tenuifolia from different geographical regions of Iran. Fifteen primers revealed 247 polymorphic bands, out of which 214 (86.78%) were polymorphic. The dendrogram was constructed using SM coefficient and UPGMA method. The generated dendrogram revealed three groups. The accessions originated from central regions of the country separated from others in group 3. The principle coordinate analysis (PCoA) confirmed the results of clustering (>90%). For morphological traits, North-western (NW) accessions had the highest values of leaf length, leaf width, leaf area, essential oil yield and the latest flowering time, while the Northern one (AtN76) had the highest flower diameter and number of florets in main inflorescence. Results showed the relatively broad genetic base of in most of the accessions evaluated in this study. The lowest and the highest gene diversity were obtained in North-western (AtNW) group (0.18) and Northern (AtN) accession (0.28) respectively. High genetic variation of A. tenuifolia might be attributed to its reproductive propagation and seed dispersal. So, conservation strategies should be provided to maintain such diversity aiming to improve future breeding programs.

Pages 128-135 | Full Text PDF

Molecular characterization of Carthamus tinctorius and C. oxyacanthus germplasm using sequence related amplified polymorphism (SRAP) markers

Majid Talebi, Niloofar Mokhtari, Mehdi Rahimmalek, Seyyed Rasoul Sahhafi

Abstract
Genetic diversity of 42 Carthamus oxyacanthus and seven C. tinctorius genotypes from five distinct geographical regions of Iran was evaluated using sequence related amplified polymorphism (SRAP) markers. Twelve SRAP primer combinations (PCs) amplified 293 fragments, of which 224 were polymorphic. The number of polymorphic fragments detecting per PC ranged from 13 to 24 bands with an average of 18.66. Average PIC value was 0.339 over all PCs. Cluster analysis using UPGMA method and Jaccard's similarity coefficient (r = 0.85) grouped the genotypes into five main clusters according to species and regions. Sum of the first three PCOs could represent most of (75.2%) the total variation in the original dimensions and confirm the results of cluster analysis. The obtained population genetic indexes revealed considerable diversity and heterozygous nature of C. oxyacanthus in comparison to C. tinctorius. The AMOVA results also showed significant differences in the genetic diversity among the species (Fst = 0.277; P < 0.0001) and regions (Fst = 0.185; P < 0.0001). The results revealed the existence of wide genetic base of safflower germplasm in Iran and the effectiveness of SRAP markers for studying genetic diversity and relationships among and within species and regions.

Pages 136-142 | Full Text PDF

Carotenoids accumulation and expression of carotenogenesis genes during seedling and leaf development in Chinese cabbage (Brassica rapa subsp. pekinensis)

Pham Anh Tuan, Nam Il Park, Woo Tae Park, Yeon Bok Kim, Jae Kwang Kim, Jonghoon Lee, Suh-hee Lee, Tae-Jin Yang and Sang Un Park

Abstract
To investigate the regulation mechanisms of carotenoid biosynthesis in Chinese cabbage (Brassica rapa subsp. pekinensis), carotenoids accumulation and carotenogenesis genes (BrPSY, BrPDS, BrZDS, BrLCYB, BrLCYE, BrCHXB, BrZEP, and BrNCED) involved in carotenoids biosynthesis were analyzed during seedling and leaf development using real-time PCR. For seedling, some of carotenogenesis genes were showed similar to expression pattern between under dark and light condition. Carotenogenesis genes reached the maximum transcription at 8 days after sowing and this was similar to the highest contents of most detected carotenoids. Carotenoids contents (mainly lutein and ß-carotene) in light-grown seedlings were several time higher than those in dark-grown ones. For leaf development, direct lighted–outer leaves contain a 30-fold higher carotenoid amount compared to inner and middle leaves. However, expression level of carotenogenesis genes in outer leaves did not show a big different with those in inner and middle leaves. These results suggest a considerable role of light in carotenoids biosynthesis during seedling and leaf development.

Pages 143-148 | Full Text PDF

Genetic analysis and QTL mapping of agro-morphological traits in sunflower (Helianthus annuus L.) under two contrasting water treatment conditions

N. Abdi, R. Darvishzadeh, M. Jafari, A. Pirzad and P. Haddadi

Abstract
The present study was undertaken to investigate the genetic basis and map quantitative trait loci (QTLs), controlling agronomic traits in sunflower under well-watered and water-stressed conditions. Recombinant inbred lines (RILs) coming from the cross between sunflower parental lines PAC2 and RHA266 were evaluated in a rectangular 8´9 lattice design with two replications in each treatment conditions. High genetic variability and transgressive segregation was observed for all studied traits in both water treatment conditions. Significant correlations were observed among studied traits. QTL-mapping was performed using a recently developed SSR sunflower linkage map. One to eleven QTLs were found for studied trait across two water treatment conditions. The percentage of phenotypic variance (R2) explained by QTLs ranged from 0.23 to 48.89%. Based on overlapping support intervals, the co-location of QTLs for studied traits was determined. QTLs controlling most of the traits were overlapped on different linkage groups, which was in accordance with the phenotypic correlation results among the traits. A comparative analysis of identified QTLs herein with those described in previous studies for drought adaptive traits revealed a number of QTLs in common. These QTLs have potential use in marker-assisted selection.

Pages 149-158 | Full Text PDF | Supplementary data

Identification, characterization and validation of SSR markers from the gerbera EST database

Daiane de Pinho Benemann, Luciana Nogueira Machado, Luis Willian Pacheco Arge, Valmor João Bianchi, Antonio Costa de Oliveira, Luciano Carlos da Maia,
José Antonio Peters

Abstract
Genic microsatellites, are currently among the best DNA markers because they often represent transcribed genes with putative function, and their cost is relatively low. In this study, 7,529 non-redundant (nr) ESTs from gerbera, obtained from public databases, were identified and characterized to validate their use as genic microsatellite markers. Of the assembled nr ESTs, 1,244 contained SSRs, and trinucleotides (GAA) were found to be the most abundant repeats at 42.3%, followed by dinucleotides (GA) at 25.3% and tetranucleotides (TTTG) at 6.2%. Gene ontology (GO) characterization was used to perform functional annotation of unigenes containing SSRs, of which 36.87% revealed significant sequence similarities with other species, indicating the top species with the highest similarity. A total of 647 primer pairs may be designed from the nr SSR-positive ESTs (excluding those with only mononucleotide repeats) for amplification of potential genic markers. A sample of 50 primer pairs was tested, and 17 were validated. The identified markers were highly polymorphic and able to differentiate 34 genotypes, representing the genetic variation within commercial and wild varieties. This study provides insight as to the frequency and distribution of SSRs in the gerbera transcriptome and demonstrates the successful development of genic SSRs. We expect that the potential markers described here can greatly expand the repertoire of DNA markers available for both breeding and genetic studies in Gerbera spp.

Pages 159-166 | Full Text PDF | Supplementary data

Review article

Proteomics of nitrogen fixing nodules under various environmental stresses

Sowbiya Muneer, Javed Ahmad, Humayra Bashir and M. Irfan Qureshi

Abstract
Proteomics is an ideal tool to study the interaction of root nodules and their symbiotic bacteria as it provides a broad overview of proteins produced by both partners during their constant signal exchange and allows the signal transduction path ways following photophosphorylation. Iron containing proteins play a key role in symbiotic nitrogen fixation that occurs in a nodule-a specialized structure present on roots. Several proteins like those related to SNF (symbiotic nitrogen fixation), predominantly components of nitrogenase complexes, such as nifD, nifH, nifK, nitrogen regulatory protein II (GlnB) and PIIA (PtsN), and urease accessory protein (UreE) have been found to be affected by abiotic stress. Nodules are better equipped with all kinds of antioxidant systems (i.e., ascorbate-glutathione pathway or Superoxide dismutase) which have been formed to show a decline under stress conditions. The present review article aims to investigate the nodule physiology, the effect of different abiotic stress on nodule proteins comprehensive account of these stress- responsive proteins and their role in combating stress in legume nodules. This will help to elucidate which specific key proteins are affected by abiotic stress. As such, it will greatly facilitate understanding resistance or stress tolerance mechanism and hence improvement in crop resistance.

Pages 167-176 | Full Text PDF

Effects of glyphosate on photosynthesis, chlorophyll fluorescence and physicochemical properties of cogongrass (Imperata cylindrical L.)

Jianli Huang, Evandro Nascimento Silva, Zonggen Shen, Bo Jiangc, Hongfei Lu

Abstract
Cogongrass is one of the most destructive weed in China. It has been reported as one of the ten most troublesome weed species in the world. Therefore, developing an effective method to control this weed has become a significant and worthwhile practice. The effect of glyphosate on this weed growth was investigated during the 2009-2011 years. The photosynthesis, chlorophyll fluorescence, chlorophyll a and b content, proline content and shikimic acid content were assessed at the second, fifth, and ninth day after treatment with different concentration levels of glyphosate (0%, 0.3%, 0.5%, 1.0%, and 2.0%) in this study. Our results showed that the chlorophyll a and b content, the net photosynthetic rate (PN), effective quantum yield of photochemical energy conversion (Yield), and the relative rate of electron transport through PSII (ETR) decreased significantly after treated with different concentration levels of glyphosate. However, the photochemical quenching (qP) and the transpiration rate (E) increased significantly with damage of glyphosate. Therefore, glyphosate could constrain the growth of Cogongrass effectively by causing adverse effects on photosynthetic pigments, photosynthesis, photochemical activity and the shikimic acid pathway.

Pages 177-183 | Full Text PDF

Comparative transcriptional analysis of caffeoyl-coenzyme A 3-O-methyltransferase from Hibiscus cannabinus L., during developmental stages in various tissues and stress regulation

Ritesh Ghosh, Bo Sung Choi, Mi-Jeong Jeong, Dong Won Bae, Sung Chul Shin, Sang Un Park, Hyoun-Sub Lim, Jongkee Kim, Hanhong Bae

Abstract
We have cloned a full-length gene, putatively encoding for caffeoyl-coenzyme A 3-O-methyltransferase (CCoAOMT), an important enzyme involved in lignin biosynthesis, from kenaf (Hibiscus cannabinus L.). Herein, we investigated the expression pattern of a CCoAOMT orthologue from various tissues and organs during development, and in response to different environmental cues. The full-length CCoAOMT orthologue of kenaf consists of a 744 bp open reading frame (ORF), encoding for 247 amino acids of 27.91 kDa and an isoelectric point (pI) of 5.43. The deduced amino acids of CCoAOMT evidenced a high degree of identity (up to 84%) with other plant CCoAOMT sequences. Phylogenetic analysis demonstrated its close relationship with the CCoAOMT of Gossypium hirsutum (ACQ59096). Kenaf CCoAOMT harbors eight highly conserved motifs: A, B, and C are putative S-adenosylmethioine (SAM)-binding motifs and D, E, F, G, and H are CCoAOMT signature motifs. According to quantitative real-time reverse transcriptase polymerase chain reaction (q-PCR) analysis, the kenaf CCoAOMT transcript was detected in all plant tissues and organs, whereas the highest expression was noted in mature flower tissues, which indicates that it might be involved in the flower development or in the biosynthesis of flower specific compound. All the treatments highly induced the expression of CCoAOMT transcripts in the stems of 3-week-old kenaf, which indicates that it might have a role in stress regulatory pathway. Among the treatments, the cold and H2O2-treated samples evidenced the highest levels of expression at 6 and 24 h after treatment, respectively, whereas the wounded and NaCl-treated samples evidenced lower expression levels, which suggest that different signaling networks are involved for stress mediated up regulation of HcCCoAOMT transcripts. The highest transcript level of CCoAOMT was detected at either early (within 12 h of treatments) or intermediate (24 h after treatments) time points of treatments, except drought treated sample. Early induction was observed in the case of H2O2 and SA (salicylic acid), and intermediate induction occurring as the result of wounding, NaCl, cold and ABA (abscisic acid). Whereas drought treated sample showed highest expression at seven days after treatment. MeJA (methyl jasmonic acid) treatment showed a complex biphasic expression which is different from others. In summary, we have cloned and characterized a full-length gene putatively encoding for CCoAOMT, which also showed stress responsive differential expression.

Pages 184-193 | Full Text PDF

Cold-induced changes of protein and phosphoprotein expression patterns from rice roots as revealed by multiplex proteomic analysis

Jinhui Chen, Lin Tian, Huifang Xu, Dagang Tian, Yuming Luo, Chongmiao Ren, Liming Yang, Jisen Shi

Abstract
Cold stress is a critical abiotic stress that reduces crop yield and quality. The response of the rice proteome to cold stress has been documented, and differential proteomic analysis has provided valuable information on the mechanisms by which rice adapts to cold stress. A global analysis of the change in protein phosphorylation status in response to cold stress remains to be explored, however. Here, we performed a phosphoproteomic analysis of rice roots following exposure to cold stress using a two-dimensional gel electrophoresis–based multiplex proteomic approach. Differentially expressed proteins and phosphoproteins were detected and identified by matrix-assisted laser desorption ionization time of flight/time of flight mass spectrometry combined with querying rice protein databases. Nineteen protein gel spots (stained with silver) showed a twofold difference in abundance of protein spots from gels with and without cold stress; these proteins were identified to be involved in redox homeostasis, signal transduction, and metabolism. Twelve of the thirteen phosphoprotein gel spots (stained with Pro-Q Diamond) that showed a twofold abundance difference were identified, including the following nine proteins: enolase, glyceraldehyde-3-phosphate dehydrogenase, nucleoside diphosphate kinase, ascorbate peroxidase, adenosine kinase, CPK1 adapter protein 2, ATP synthase subunit alpha, methionine synthase 1, and tubulin. Phosphorylation site predictors were used to confirm that the identified proteins had putative phosphorylation sites. These results suggest that phosphorylation of some proteins in rice roots is regulated in response to cold stress.

Pages 194-199 | Full Text PDF | Supplementary data